Temperature indicator



Jan. 9, 1923.

I. SWANBERG.

TEMPERATURE INDICATOR.

IIMIIRHHWIIIHHII.

7a ...NNISIH I \I III I ai FILED DEC. 18. A1919.

*n Patented Jan. 9, 1923.

`JI1IUS SWANBERG, OF CHICAGO, ILLINOIS.

TMP'E'RATUR InnIcArroR.

Be it yknown that' I, JnLrUs SWANBERG, a citizen of' the AUnited States, and' a resident of the city of Chicago, in the county of @ook and' State' of Illinois, have" invented certain nenY and useful Improvements in a 'leinperature ndicatorg'and' l dof hereby de- Clare thatitlie following'is a full, clear, and exact description" of the saine, reference beinghad tothe accompanying drawings,- and toftlnez numerals of reference Inarllfedy thereon whichrv foi-fn avrv part;` offthi's specification.

This' invention relatesito temperature indicators, and" although not limited to' such u'sfe, is` particularly applicable for indicatf .vithoiit'L the. aid of electrical batteries, circuitstv or complicated mechanical apparatus. @ther and' further important objects of this invention Willbeapparent from the disclosures inthe specification andy drawings.

The invention'V (in a preferred form) is 'illustrated in the drawings and hereinafter more fully described.

ln the drawings: Figure l is aside elevation of adevice einbodyin'g" the features. of' the presentinvcntionly Figure Qfs a longitiidinalicentral section through'the device prior to operation by rise 1n temperature:

Figure 3 is av View similiar to Figure' 2' showingl the position o't'the parts after operation; ,c 1

Figure 4 is a `transverse Central section through the' thermostatic device; e y

. Figur'eV is a section on the liney 5450i' Figure-2.

Figure 6 is a 'sectioionfthe linee-'6 of Figurer p y y A Figuiec'is a v'ie'w`showing a modification or"the"invento'nil l y As shownl in the drawings '2 eeenerueion illustrated et@ 1 a provided' havingla pointed; cap 2' at' one end tof allow" Such end toy be thrust into a"`stack of harvested material Which is liable tobecfonie'heatedsuch-a's hay', corn or the like. Signalling" devices are provided at?y the" other tend' or the tube operatedfbythermost'aticfapparat-us adjacentthepointed capwhenei'fer the teii'i'perature around the cap exceeds a predetermined limit.

Tlie'therrnost'atio device may conveniently consister-an annularv ring 32th the underside '0f-:Which afdiscv 4e is secured by' readily fusible metal or other material. y As shownfthe ring 3'; is h'eldin1 position inthe' lower part of the eliefigby restingiupon entree-@amie plefon the end-or the cap 2'.

Perforatioiis 6 are provided in theca-p' 2,

andfif desired, an` inwardly projecting Shoulder may beVr provided againstwhich it may helclarnpze'dby sa nipple so that' the air, steam or other' 'gafse in the stack `niay conde intocontact; Withfftlie'ring and disc 4T, SO aS toim'lt flaisibl material 3S SOD 'as the' teiii'perature of' the staclat that' point exceeds the melting point ofthe material.

The" disc' l supports the lower-'end ofl a plunger 7, sliidi'ibl'ym'untedy Within the tube untill the fusible'fmate'ril 'nieltsfandallows the disc 4L andw'ith it*` tlieplunger 7" to ,fall.

This inoveinent of theplunger niay'be'jar; ranfged to give indication'thatthe,tempera VL'ture in the stack has exceeded' the'predeter- 'inined limitv in Var1ous`- Ways'.` In the drawings both* ak visual and an`-felectrie method ln Figures l, 2f'and31thejtiibe'l isprovided with'y a series' of-slots 8vv arrangedsymmarieniyv mund: the-'mbewiua which is is visible from thef outside', While' at' the y saine t'irifle the 'entrance of hay,"str'aw, leaves or "dirt into the interior' of'thetube isy preyvented. f

"conveniently coloredfred'lower'part 1-1 and a connecting." rodI or' spindle' 12g/conveniently colred Wlitefrthe purpose of enabling ltlie position oftheplunger tobe readily de- Noriiia-lly the White roda l2 is visible' tlir'ouglifthe Windows in theltnbe l iorined: by the" slots and' the glass tube 9. lllh'e; f however', fthe plunger 7' dropsy the red portion l() becomes rVisible and acts as a "warning" tethe owner' of the stack! In order to preient tfle'jj' plunger moving further tion 'l0 to view, suitable stop mechanism may be provided. such as pins 22, adapted to engage the lower part 11 of the plunger, as shown in VFigure 3.

ln the construction lindicated in Figure 7,V

insulating block 16 to avoid short circuiting of the contacts by the plunger. In the structure shown in Figure 7, provision is made for both electrical and visual signals, the upper part of the glass tube for the latter' being shown at- 9. f i

lt is desirable that as little of the heat communicated to the ring 3 and disc 4 by the gases passing through the perforations 6 be conducted away by the plunger. Consequently the lowermost end 17 of the plunger 'l' is reduced in diameter and provided' with a conical tip 18 of hea-t insulating material such as wood or the like. A

While usually the weight oie the plunger may be utilized to operate the signal, it is also desirable that the apparatus may be thrust horizontally into the stack and :tor that purpose a spring 19 is provided for pressing the plunger against the disc L1. This spring bears on one side against the part 11 of the plunger and on the other against an annular shoulder 20, formed by indenting thev wall of the tube. This shoulder 20 also serves the purpose of restricting movementof the glass tube 9 in one direction` while movement of the tube 9 in the opposite direction is prevented by the cap 21.

The operation is as follows:

The device is thrust into a stack ot harvested material with its pointed end substantially in the center' of: the stack and its opposite end exposed so that the position of the plunger in the tube may be readily observed.

lvhcn the temperatinc in the middle of the stack has risen suiiicicntly to meltthe readily `fusible material which secures the disc 4 to the ring 3. the plunger slides in the tube under the action ot the spring 19, and also its own weight il' the tube 'is vertical or vertically inclined. This .movement ot the plunger brings its red portion l0 into view. Y ssoon as the owner of the stack sees the red'portion he pulls out the indicator and turns over the material of the stack to allow it to cool off.

The indicator .is re-set for further use by unscrewing the cap 2, removing the ring 3 and the loose disc l and inserting a second fng 3 with a disc e attached thereto by fus- On the end or thev upper part 10 of the plunger is mounted an' ible material. In this way the indicator may be used an indefinite number of times, cach time inserting a fresh thermostatic disc.

l am aware that numerous details of construction may be varied through a wide range Without departing from the principles oi this invention, and I therefore do not purpose limiting the patent granted other wise thanv necessitated by the prior art.

l claim as my invention:

1. A temperature indicator comprising` a tube having a wind-ow in one side thereof, a member slidable therein having parts ot ditilerent color adapted to register successively with said window, a. spring for moving said member and means itor holding said member and spring in retracted position until a predetermined temperature has been reached.

A temperature indica-tor comprising a tube having a window in one side theerot, a member slidable therein having parts of diiiierent rcolor adapted to register successively with said window, and means for prevenu ing movement ol said member until a predetermined temperature has been reached.

3. A temperature indicator comprising a tube having` an opening in one side thereof, a. member slidable therein havingparts visnally distinguishable from each other adapted to register silccessively with said opening. an annular ring in the tube below the slid able member` a disk secured to said 'ring by readily fusible material, and heat insulating-tip on said slidable member in contact with the disk.

a. A temperature indicator comprising a tube, a perforated cap threaded into one end of the tube a renewable disc between said cap and said` tube comprising an annular member and an inner central member secured together by readily fusible material, a member slidable in the tube bearing against said inner member, and signalling1 means operated by sliding movement; ot' the member when released by the melting ot the readily Fusible material.

5. A n temperature indicator' comprising a. tube having a window adjacent one end` thereof. a perforatedV cap threaded into the other end of the tube, an annular ring clamped between said rap and said tube. a

4disc secured to said ring hy readily Yfusible material, a member slidahle in the tube haringat one end parts ot dill'erent color :1..daptH ed to resister snrrcssivrly with said window and a spring `For pressing the other end of the member ',nst said discy whereby nielting ol the readily tusiblo n'iaterial results in movement ot said member.

6. A temperature indicator comprising a color adapted to register :successively vwith.

said Slots, additional electrically operated signal means operated upon movement yof vthe member, and means for preventing arated by Said slidable memberand adapted to spring together when the Slidable member 15 y is released by the separationof 'the fusibly -oonnected'members due to the fusing of the connecting` material, f

In testimony whereof have hereunto subscribed my name inthepresence of two 20 f subscribinzgr` Witnesses.

y JULIUS SWANBERG.

Witnesses: l e

EARL M. HARDINE. CHARLES W.` HILLS, J r. 

